Sunday, February 27, 2011

By now, I know most people are aware of what it takes to lose weight, and more specifically to lose fat. With all due respect to the quality of the calories you eat (I'm not covering that today), the generic and essentially correct thinking is calories in must be less than calories out to lose weight. Many people take this as a literal translation, meaning the bigger the deficit between calories I eat and calories I burn, the more weight I'll lose. This is not necessarily true. The body doesn't like having to few calories, and at a certain point, will begin to make adjustments to create balance between incoming and outgoing calories (caloric homeostasis). Let’s first think about how the human body uses energy. When we eat calories, they are converted to energy, when you eat enough to fuel your body, no problem, you're in balance like a see saw with the same amount of weight on both sides; but when the total amount of calories you burn in a day through just living, and exercising, and regular daily activity is more than what you're eating, your body has some choices to make about where to get enough energy to make it up. It'll first use the stored energy it has in the liver and at muscles, called glycogen. Unfortunately, you don't have a heck of a lot of glycogen, so that's only good for a little bit extra. Next the body will turn to body fat, and that's great, but your body burns body fat like an ice cube melts, by that I mean, you can only burn so much at a time. Next up is muscle mass, the body will pull energy from muscle as a last resort, cannibalizing the least used muscle first in most cases. If all of these extra calories STILL don’t equal what you are burning, then the body will take drastic measures and start slowing down the metabolism. See my prior blog on short and long term fasting for a more in depth description of this process.

So, because of what we just outlined, there's a sweet spot for the body. Roughly this is the calorie deficits that allows you to burn fat, but not start pulling energy from muscle, and definitely not start lowering the metabolic rate. How do you know how much? Well, you usually don't, not at first at least, and this number will change as body fat percentage changes. That being the case, a little experimentation is usually in order. The first thing you need to know is roughly how much energy you burn in a day; to know that you can use a few different methods. The easiest method is to just use one of the tons of maintenance calorie calculators on line. I prefer the one at webmd.com (http://www.webmd.com/diet/healthtool-metabolism-calculator). The number won't be perfect, but it's a good start. To be a little more accurate, you might consider something like a body bugg. Please note, a body bugg is different from a regular HRM(calorie counting heart rate monitor) as HRM's have a hard time calculating calorie expenditure at normal heart rates (HRM's are essentially ECG machines and because the impulse from your heart is low during rest periods, it can misread these beats often) Body bugg type devices are far more sensitive (thus the reason they are so expensive) which means they are more accurate during low heart rate periods (such as sleeping). Lastly you can go to a lab and have a metabolic rate test done. These are generally the most accurate, but if you are having a "bad" day, it could be off (and remember, stress over GOING to the lab could affect the outcome). However you do it, you need a baseline of your daily calories.

Once you know your calories, you can start thinking about a deficit. Remember, we're looking for the sweet spot for calorie deficit. That means you want enough of a deficit to lose fat, but not too much where you're burning lots of protein or lowering your metabolic rate. To do this you should analyze your fat. Obviously, if you know your body fat percent, that's the best way to make a decision. But sometimes it's not easy to receive an accurate body fat test. Home scales are wildly inaccurate for body fat (they use hydration for their calculations, which can vary greatly day to day, thus giving really wide margins for error). If you can't have a body fat test, the next best thing is to use BMI. I am not a fan of BMI in general, but in the absence of body fat, it's essentially all we can go on. Just be sure to remember that BMI does NOT take into account muscle mass, so if you are heavily muscled, the BMI can inaccurately report obesity. Also women who are or who recently were pregnant shouldn't put much stock in BMI. That out of the way, your BMI number will give you a general starting point for deficit, for most people if you are obese (BMI of 31 or greater), you can have a relatively large calorie deficit, somewhere north of 1000 calories per day, the higher the BMI, the bigger (within reason) the deficit. The lower your BMI, the smaller the deficit. I usually tell clients that if your BMI is over 30, go for 1000 and see where that leads you, 28 to 30 I usually give a deficit of about 750 calories, between 25 and 28 I say about 400 to 600 calories, and below 25, if you want any deficit, it should never be above 300. I realize that this may seem rather small to some, but that's the reality of HEALTHY weight loss. It's never going to be super fast. And it shouldn't be, because if you want this to stick, losing fast weight isn't the answer, you need to give your body time to adjust.

On to the subject of adjustment; after the initial calorie goal is set, you should monitor and tweak, if it's not working like you suspected, tweak. Remember this though, any tweaks you make to calories should be relatively small, 100 calories per day changes is my recommended maximum. And in order to evaluate that tweak, you should give yourself at least 1 month at the new level. The human body doesn't react that quickly to changes in eating habits, so expecting changes in days or weeks is not realistic.

Lastly let’s talk about maintaining. Once you reach your end point and have reached a body fat percentage you feel comfortable with, you need to SLOWLY raise your calories, usually over the course of 6 to 8 weeks, back to maintenance. If you've followed what I've written above, you've probably already adjusted your calorie deficit as you approached your goal weight. If you have, then your deficit should be relatively small, and your body shouldn't have a hard time adjusting to maintenance. One of the main reasons why so many people fail after dieting is because they fail to properly come out of the "diet mode" and into maintenance. If you suddenly go from a 500 calorie deficit to maintenance, the body will inevitably try to put some weight back on. Give your body the chance to adjust and it won't feel the need to pack on extra fat.

Please note that I'm not going into the concept of exercise calories. All calorie amounts I talk about here are NET calories. Which means daily calories PLUS exercise calories. So a deficit of 500 calories would mean your daily calories plus exercise calories minus what you eat should equal a 500 calorie deficit.

As most know, obesity is more than just being overweight. Besides the physical health risks assigned to obesity, the mental aspects of the condition are a major concern and in my opinion is the underlying reason not only for the weight gain, but also other symptoms that the person can identify with.

As an animal, humans don't have a genetic propensity to excessive weight gain. Unlike some other species of mammal that use fat as a a layer of insulation such as whales, or as a storage mechanism for lean winters such as sea lions or bears, humans don't have a semi-seasonal clock which can help to regulate the metabolism in times of low energy availability, nor do they have the skeletal structural mechanisms to deal with excessive weight gain (I.E. 4 legs to balance additional weight, or water to mitigate stress on joints). So being obese for a human is far more of a problem than it is for other animals.

These are the well-recognized, physical problems that can come from obesity. What about the mental aspects of obesity? In both the mental ramifications of being obese, and the causality for the obesity; I am a firm believer that almost all obesity, and weight related maladies that have not been identified by a specific physical medical cause (such as hypothyroidism or metabolic syndrome), can be tied back, at least partially, to psychological foundations.

When tackling the psychological aspects of obesity, we first must identify the trigger that causes someone to eat. Many times food is associated with comfort, security, safety, and happiness for the obese individual. Other times control issues manifest in the obese individual to gain weight. Psychological trauma from earlier in life can be a precursor to weight gain later. Often times, people with obesity issues use food as a control mechanism. when faced with triggers such as a stressful family environment, they turn to eating because they feel like their body is the one thing they have absolute control over, and eating is a natural way to react because food in most people's mind is associated with comfort and happiness. Some people cut themselves, others turn to drugs, and some turn to alcohol; food is fast becoming the method of choice for people who have unresolved psychological trauma.

Not all obesity is so obscured though. Sometimes the psychological issues induce stress, and stress releases a certain set of hormones in the body, chief among them is cortisol, a hormone released by the adrenal gland during high stress periods in order to increase vasodilation (meaning it widens blood vessel for higher blood flow) and increase oxygen delivery. Unfortunately, cortisol also inhibits insulin sensitivity, which means more blood sugar in the body, and a higher rate of body fat storage. During times of exercise related stress, cortisol is a good thing; it allows the body to focus on burning fuel, and burn it faster allowing increases in strength and speed accordingly. This quickly dissipates the cortisol without much in the way of follow-on problems; but when stress comes from non-physical means, or there is no accompanying high intensity physical activity with the cortisol uptick, that's when this condition becomes a net detriment to the body. When stress levels are consistently high for long periods, people develop areas of fat, even if they don't significantly over eat.

So we have two distinct causalities for obesity, one is a means to mitigate psychological trauma; another is a biochemical response to high stress periods over long timelines. Both are obviously psychological causalities, and both require different treatments.

I feel that in both cases, cognition of the underlying causes is vital to resolution. I.E. a person can do all the extreme diets in the world, or receive weight loss surgery, or take pills; these are resolving symptoms of the root cause, but they aren't addressing the main problems, and thus, these treatments will only work in the short term. These types of extreme resolutions only feed the overall issues that people associate with the obesity. When they inevitably fail to keep the weight off, it adds to their feelings of failure and inadequacy, thus allowing for more potential of weight gain. Gradually becoming a vicious cycle of weight loss, weight gain, more weight gain, depression, and resolve and starting over again. Unfortunately, eventually this takes its toll on the body and weight loss becomes more difficult, and as the person’s physical ability to lose weight lessens, so does their mental strength to fight the obesity.

I make no case to solve obesity in any one specific way, as each person requires slightly different techniques to solve their issues (thus no one diet or pill will ever cure obesity), I will say that stress reduction techniques, and mental health counseling are a big part of any plan.

Saturday, February 19, 2011

Per reader request, and in the interest of making this as easy as possible to reach the broadest amount of users, I've added a less technical version to the end of this post. If you start reading this, and cannot make heads or tails of it, please skip to the section at the bottom in italics, it should be far easier to understand, although it will miss some of the technical details that the first section has.

There are two separate and distinct classifications for fasting and/or underfeeding. Those two areas are short term fasting (< 3 days) and long term fasting (> 60 hours), here I'll describe both. See the link I posted above to learn more. There's a lot of research out there, I'm not going to cite it all, but it's available, and if you want to do more research please email me and I'll try to find what you are looking for.

Overview The human body stores energy in the form of glucose, which is arranged in large groups called glycogen and is stored in an aqueous medium in the liver and to a lesser degree in muscle sites. Glycogen is what the mitochondria in cells use to facilitate energy production and Adenosine Triphosphate (ATP) production, which is the actual chemical the body uses for energy. While ATP can be generated from both glycogen directly or via the Krebs cycle (citric acid cycle) using pyruvate generated from protein and/or fats, glycogen is by far the preferred medium for this operation because of the amount of ATP it produces (far more than the Krebs cycle) and the speed at which this is accomplished. The other thing to keep in mind is that the brain, which uses about 20% of the energy from the Resting Metabolic Rate (RMR) cannot use fat as energy because of the size of lipoprotein molecules and the blood-brain barrier. Glucose or ketone bodies are required for brain and CNS energy. This will become important later so I thought I'd give it now as a baseline.

Short term fasting STF means the lack of incoming energy for between 6 and 60 hours. In the initial stages of fasting, the body does not recognize fully the lack of fuel and continues using glycogen and fat (via lipolysis) for energy. During this time hormone production continues on as usual. In some cases the Active Metabolic Rate (AMR) can actually go up slightly causing a small increase in energy output. This is a good time to try for fat loss while maintaining a healthy energy balance in the body. If performing full fasts (no incoming energy), this state usually lasts for 24 to 36 hours, if performing extreme underfeeding in an adult with normal body fat levels (non-obese individuals) usually characterized by 600 to 1000 calorie per day or higher deficit and assuming micro-nutrient levels are sufficient; this state can last up to about 60 hours or longer. For obese individuals the rise in AMR is usually not seen, nor is the rise in lipolysis, but the state can last for weeks depending on the amount of available fat to be used for energy. The body will begin to prioritize the brain for glucose use, which is fine while glycogen levels are sufficient. Whole body energy can be maintained via the freeing of lipoprotein from adipose fat and the conversion of protein into pyruvate and ketone bodies.

Long Term Fasting LTF begins when the body's glycogen levels are depleted. When this happens certain distinct changes in the body become evident. Urea nitrogen levels rise due to the increase in protein usage and fat sparring (nitrogen is a byproduct of protein conversion to usable energy in the Krebs cycle). Adipocyte cells begin producing higher levels of cortisol which is a hormone designed to mitigate the effectivness of insulin. With the rise in insulin resistance comes the reduction of blood sugar effectiveness and the subsequent slow down of RMR. In the short term, studies have noted an 8 to 15% decrease in RMR with longer term results reaching up to about 30% (in > 15 days). Other changes are a decrease in testosterone output and growth hormone levels, although it's not known as yet whether this is caused by the reduction in RMR or a reason for that reduction. Coupled with this change is the shift from a glucose burning metabolism to a fat and protein burning metabolism which focuses on the reduction of unused lean tissue (to help prevent unneeded energy waste that occurs from all lean tissue) and the increase in fat storage due.

Personal thoughts on this process and conclusions I glean.While these facts are all from studies, the case is not yet closed on long term or short term fasting and more research is needed. But to date it's believed by myself and many others that while the term "Starvation Mode" is thrown around the nutrition community with reckless abandon, it's not a myth, it's simply misunderstood. People in the nutrition community need to make a better effort to understand how much energy is needed to stay out of LTF states, and allow the body to continue burning fat while minimizing the risk of excess protein burn.

There are at home tests available that can measure urea nitrogen levels, this can help in some cases to determine whether a person is using excess protein as energy and possibly help to keep a client or patient from entering the dreaded "starvation mode". Specifically for those people looking to lose small volumes of fat. Obese people have a larger window in which they can afford large calorie deficits without inflicting serious long term muscle and organ damage, but for those with only a modest amount of fat, that damage can begin in weeks, despite their best effort. And because of the insidious nature of energy deprivation, and the lack of easily readable signs, people will continue to use large deficits to lose small volumes, which is a losing proposition in the long term.

Less technical version.Us humans use a sugar based solution called glycogen for energy to run our muscles and organs. This energy comes mainly from carbohydrates. And without going to deeply into it. We store this glycogen mix in our liver, and a little in our muscles.

In short term fasting, our body has enough stored energy to work normally for between 24 hours and about 60 hours, the exception being people with large fat stores (obesity), where the change can take as long as 15 or more days depending on how obese the person is, and a host of other factors. Essentially this means that you can fast(eat nothing) or undereat (eat less than maintenance calories) for a period of hours or days and not aversly affect your metabolic rate and not diminish how your body burns extra fat.

In long term fasting, the body has finally run low enough on stored energy that it begins reacting to the deficit. The body starts changing the hormones that control how, how much, and what we burn for energy in an attempt to conserve body fat (a famine response) and burn as little as possible. When this happens we burn less energy than normal (which is bad, it means we have less energy), our body begins to canabalize muscle tissue, and the immune system is less effective. Eventually, if it continues long enough, organ function can be compromised, and certain specific medical conditions can occur. We are not sure exactly when this process begins because of the extremely complex nature of the human metabolism and the difficulty in measuring in vivo (inside the body)chemical amounts during changing conditions (it's very inefficient to try to draw blood every 10 minutes for 2 days to see the changes in hormone levels). My summation is basically saying that the concept commonly known as "starvation mode" actually represents long term fasting, and while the term is commonly misused, that doesn't make it a myth, it makes many people's perception wrong only. I also say that while these things I say are strongly correlated theories, they are not fact, as there is still more research needed to confirm these things. But in the abscense of more data, it's all we can go on.